From 619015cf633dbe84b48f61c4bbfe4058d962a635 Mon Sep 17 00:00:00 2001
From: mike lowis <mike@mdlowis.com>
Date: Thu, 6 May 2021 23:51:15 -0400
Subject: [PATCH] started implementing array subscripting

---
 cerise/oberon0/OSP.Mod |  6 +++++-
 cerise/src/grammar.c   | 23 +++++++++++++++++++----
 cerise/tests/Module.m  |  4 +++-
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/cerise/oberon0/OSP.Mod b/cerise/oberon0/OSP.Mod
index dd90229..ecaf363 100644
--- a/cerise/oberon0/OSP.Mod
+++ b/cerise/oberon0/OSP.Mod
@@ -272,11 +272,13 @@ MODULE OSP; (* NW 23.9.93 / 9,5.2017   OSPX*)
         factor(y);
         CheckInt(y);
         OSG.MulOp(x, y)
+
       ELSIF (op = OSS.div) OR (op = OSS.mod) THEN
         CheckInt(x);
         factor(y);
         CheckInt(y);
         OSG.DivOp(op, x, y)
+
       ELSE (*op = and*)
         CheckBool(x);
         OSG.And1(x);
@@ -322,11 +324,13 @@ MODULE OSP; (* NW 23.9.93 / 9,5.2017   OSPX*)
 
   PROCEDURE expression0(VAR x: OSG.Item);
     VAR y: OSG.Item; op: INTEGER;
-  BEGIN SimpleExpression(x);
+  BEGIN
+    SimpleExpression(x);
     IF (sym >= OSS.eql) & (sym <= OSS.geq) THEN
       op := sym;
       OSS.Get(sym);
       SimpleExpression(y);
+
       IF x.type = y.type THEN
         OSG.Relation(op, x, y)
       ELSE
diff --git a/cerise/src/grammar.c b/cerise/src/grammar.c
index da646dd..4140051 100644
--- a/cerise/src/grammar.c
+++ b/cerise/src/grammar.c
@@ -112,10 +112,25 @@ RULE(designator)
 //            expect(p, IDENT);
 //            break;
 //
-//        case '[':
-//            expr_list(p);
-//            expect(p, ']');
-//            break;
+        case '[':
+        {
+            expect(p, '[');
+            Type* type = item->type;
+            while (type && type->form == FORM_ARRAY)
+            {
+                Item expr = {0};
+                expression(p, &expr);
+                check_int(p, &expr);
+                type = type->base;
+                if (type->form == FORM_ARRAY)
+                {
+                    expect(p, ',');
+                }
+            }
+            expect(p, ']');
+            break;
+        }
+
 //
 //        case '^':
 //            expect(p, '^');
diff --git a/cerise/tests/Module.m b/cerise/tests/Module.m
index fc5d28e..fc74734 100644
--- a/cerise/tests/Module.m
+++ b/cerise/tests/Module.m
@@ -21,6 +21,7 @@ var
   b : Int
   c : Int
   d : Real
+  e : TypeB
 
 procedure Foo*(e : Int, z : Int) : Int
   const FOO = 2
@@ -100,5 +101,6 @@ begin
 #  end
 #
   # Function calls
-  c = Foo(1,2);
+#  c = Foo(1,2);
+  e[0] = 1;
 end
-- 
2.49.0